Enter your 12-digit Aadhaar Number in the field and click on Send OTP. You will then receive a One Time Password (OTP-valid for only 15 minutes) on your registered mobile number. If your mobile number is not registered then you will be asked to input your mobile number on which your OTP will be sent. Enter the OTP received on your mobile and the text visible on the screen and click on Login button. Be quick because your OTP is valid for 15 minutes only.